Linking tradition and future – first-time isolation of plant extracellular vesicles from the medicinal foxglove

Extracellular vesicles (EVs) are membranous vesicles released by mammalian, plant or bacterial cells that carry complex cargos, including lipids, proteins, and nucleic acids and mediate cell-to-cell communication [1]. Digitalis species are pharmaceutically relevant plants as they contain cardiac glycosides that are used to treat cardiac insufficiency and show promising antiviral and antitumoral activities [2, 3]. In addition saponins, pregnane glycosides and phenlylethanoid glycosides are the main natural compounds of this genus [4]. Here, we isolated plant EVs (PEVs) from the apoplastic fluid or the culture media form Digitalis shoot cultures (SC) as well as no-cardenolide-containing cell suspension cultures (CSC). Nanoparticle tracking analysis (NTA) verified the presence of particles with a particle concentration range from 109 to 1012 (P/mL) per g fresh weight (FW), presenting a predominant size from 115 to 190 nm. PEVs were isolated with a significantly higher yield and uniform size from CSC compared to SC. Digitalis PEVs remained stable for two weeks at 4°C. Treatment of Digitalis CSC with 10 µM of IAA increased PEV production up to a particle concentration of 1013 (P/mL) per g FW. Cryo-TEM images showed spherical, oval or rod-shaped particles. Treatment of A549 NSCLC cell line for 24, 48 and 72 hours with PEVs isolated from Digitalis SC or CSC decreased cell viability to around 65% and lower. All in all, PEV derived from the medicinal plant Digitalis seem to have a bioactivity that is exciting to study further for example, in regard to their cargo of either secondary metabolites, proteins or miRNAs.

 

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Publication History

Article published online:
16 November 2023